Some Other Security Systems
Passwords on UNIX are stored using a hash based on encrypting 0 with a DES like secret algorithm with key based on password
Kerberos is a secret key cryptography system using a KDC -- Key distribution center which keep authorized people and their master keys
Sessions are assigned dynamically session keys which are used to encrypt with DES transmissions
Electronic mail systems include PEM (Privacy Enhanced Mail) which could use Kerberos like secret keys but in practice is based on public key certification with again DES for message transmission
PGP (Pretty Good Privacy) is similar to PEM and used for mail and file transmission
- Note difficulties is public key certificate. This area will get a lot easier when Internet shopping promotes public key certification strategy